to be as ugly as sin, to be as ugly as a scarecrow
Contexto
At first they couldn’t figure her out. She was as plain as homemade soup, one guy said. She was as ugly as a mud fence, said another. Some of them thought she was a man, even after seeing her several times. But she had an energy and a vitality that charmed them, a deep-throated laugh, a sense of fun and adventure and abandon that they saw in themselves and admired in her.